NEHRP Clearinghouse
- Title
- Flexural Retrofit of Circular Reinforced Concrete Bridge Columns by Steel Jacketing. Experimental Studies.
- File
- PB95239950.pdf
- Author(s)
- Chai, Y. H.; Priestley, M. J. N.; Seible, F.
- Source
- California State Dept. of Transportation, Sacramento. Office of Structures Design.; California State Business and Transportation Agency, Los Angeles.; Federal Highway Administration, Sacramento, CA. California Div.; National Science Foundation, Arlington, VA., October 1991, 172 p.
- Identifying Number(s)
- UCSD/SSRP-91/06
- Abstract
- Collapse or severe damage of a number of California Bridges in recent moderate earthquakes has emphasized the need to develop effective retrofit measures to enhance the flexural strength and ductility, as well as the shear strength, of bridge columns designed before current seismic design provisions were implemented. This report presents the results of an experimental study in which the potential plastic hinge region of circular bridge columns is encased with a steel jacket for enhanced flexural performance. Results from large-scale column tests showed that the steel jacket acts efficiently as confinement reinforcement, enabling column ductilities exceeding those designed with current codes to be achieved. The jackets also inhibits bond failure in the lap-splices of the longitudinal reinforcement by restraining the dilation and spalling of the cover concrete which would otherwise precipitate rapidly degrading bond failures. Steel jacketing is also effective for post-earthquake repair of columns which have suffered bond failure at the lap-splices of the longitudinal reinforcement. The tests identified brittle shear failure at the footing/column joint as a potential failure mechanisms for old footing designs.
- Keywords
- ; Reinforced concrete; Columns (Supports); Deflection; Bridge maintenance; Design analysis; Ductility; Earthquake resistant structures; Retrofitting; Earthquake damage; Buckling; Highway bridges; Structural steels; Circular bodies; Bridge design; Highway maintenance; Structural analysis; Reinforcing materials; Flexural strength; Earthquake engineering; Bending moments; Reinforcement (Structures)